Turning back to the Lower Computing Room, we notice in it the stone pier, already alluded to, which was set up by Halley, and formed the first addition to the original Observatory of Flamsteed. The Lower Computing Room itself and Bradley's Transit Room were due to the Astronomer after which the latter is named. An iron spiral staircase in the middle of the Lower Computing Room leads up to the Upper Computing Room, and above that to the Astrographic dome, so called because the twin telescope housed therein is devoted to the work of the Astrographic Chart--a chart of the entire sky to be made by eighteen co-operating observatories by means of photography. In this way it is intended to secure a record of the places of far more stars than could be done by the ordinary methods, and in this project Greenwich has necessarily taken a premier place. This is a work which, whilst it is the legitimate and natural outcome of the original purpose of the Observatory, is yet pushed beyond what is necessary for any mere utilitarian assistance to navigation. For the sailor it will always be sufficient to know the places of a mere handful of the brightest stars, and the vast majority of those in the great photographic map will never be visible in the little portable telescope of the sailor's sextant. But it will be freely admitted that in the case of an enterprise of this nature, in which the observatories of so many different nations were uniting, and which was so precisely on the lines of its original charter, though an extension of it, it was impossible for Greenwich to hold back on the plea that the work was not entirely utilitarian. Descending again to the Lower Computing Room, and passing through it, not to the east, into Bradley's Transit Room, but through a little lobby to the south, we come upon an inconvenient wooden staircase winding round a great stone pillar with three rays. This pillar is the support of Airy's altazimuth, and very nearly marks the place where Flamsteed set up his original sextant. Returning again to the Lower Computing Room, and passing out to the east, just in front of the Time Superintendent's desk, we enter a small passage running along the back of Bradley's Transit Room, and from this passage enter the present Transit Room near its south end. Just before reaching the Transit Room, however, we pass the Reflex Zenith Tube, a telescope of a very special kind. Immediately outside the Transit Room is a staircase leading on the first floor to two rooms long used as libraries, and to the leads above them, on which is a small dome containing the Sheepshanks equatorial. These libraries are over the small sitting-rooms already referred to. The fire-proof Record Rooms, two stories in height, terminate this range of buildings.